1. Field of the Invention
This invention relates to a receiving device for receiving on the ground microwave signals from communication satellites, broadcasting satellites and so on, specifically a receiving device comprising a plane antenna, a low-noise amplifying circuit connected with the plane antenna, and so on.
2. Related Background Art
Accompanying the rapid development of information networks, the demand for satellite communication systems is on rapid increase, and frequencies in the microwave band are increasingly used. As high-frequency field-effect transistors, Schottky barrier field-effect transistors (MESFETs) of compound semiconductors, as of GaAs or others, are practically used. Furthermore, recently first stage amplifying units of downconvertors for converting high-frequency signals to low-frequency signals are increasingly provided in microwave monolithic integrated circuits (MMICs).
On the other hand, plane antennas begin to be practically used as antennas for receiving on the ground microwave signals from communication satellites and broadcasting satellites. A plane antenna comprises a number of antenna elements arranged in plane, signal powers received by the respective antenna elements being collected by conductors. The plane antenna for receiving microwaves was at start far behind parabolic antennas in terms of performance and costs. But since the latter half of the 1970's microstrip antennas have been increasingly studied, and the performance of microwave print substrates have been improved, and presently microstrip antennas have reached the practical level.
But the means for connecting the receiving circuits provided in MMICs to plane antennas has not been sufficiently studied. For example, in using, as means for connecting both, a waveguide, which is common microwave transmission means, it is difficult to achieve the miniaturization and the reduction of a weight as a whole, and the successful miniaturization of the receiving circuits and the successful planarization of antennas cannot be made effective use of.